The usual cargo transfer vehicle used to on and off-load aircraft includes an elevatable platform assembly whose outer cargo transfer end is adapted to abut flush against an aircraft fuselage just below a cargo hatch. The positionment of such platform assembly is conventionally effected by vertical adjustment of the platform assembly and by advancing movement parallel to the vehicle centerline. The advancing movement, desirably, takes place in two stages with the initial advance being that of vehicle approach to the aircraft which terminates just short of contacting the platform assembly with the aircraft fuselage to avoid possible damage while the final advancing movement to abut the cargo transfer end of the platform assembly against the fuselage is manually effected by linear extension of the platform assembly relative to the vehicle. Accordingly, if the vehicle is not maneuvered to position the centerline thereof perpendicular to the plane of the hatch opening, one side of the outer, cargo transfer end of the platform assembly will abut the aircraft leaving a gap or generally sector shaped opening adjacent the other side of the platform assembly.
In the case of certain aircraft, exemplified by the Boeing 707 and 747, the cargo hatch is positioned to permit of a straight on vehicle approach perpendicular to the centerline of the fuselage while on some aircraft, such as the Boeing "stretch" 727, the relative positioning of the cargo hatch to the engine nacelles and/or wings dictates that vehicle approach take place along an arc which positions the vehicle at an acute angle to the fuselage. Thus, in the former instance, a sector shaped opening or gap may result simply from inaccurate vehicle approach while, in the latter, the gap that will necessarily be present is obviously magnified if vehicle approach is not accurate along the greatest permissible arc. In either event, if such gap is of substantial dimension it is necessary to back the vehicle for a subsequent approach.
The difficulty in making a first, accurate approach is readily understood from a consideration of the fact that the driver of the vehicle is making a virtual "blind" approach insofar as the relationship of the cargo transfer end of the platform assembly to the aircraft hatch is concerned. That is to say, the cargo transfer end of the platform assembly is normally positioned above and forward of the vehicle cab so that the driver lacks a vertical or other reference plane to "guide on", and his only unobstructed view during final aircraft approach is of the convex under portion of the fuselage.
When the approach is other than perpendicular to the aircraft centerline whether by reason of necessity in the avoidance of aircraft structure or inaccurate vehicle maneuvering, the result is that the cargo transfer end of the platform assembly is not positioned to flushly abut the fuselage, and it is the purpose of the present invention to provide an elevatable platform assembly which is manually adjustable to accommodate such misalignment.